Stress to improve our health: The case of Hormesis

I had a tough childhood. I was happy to have enough food (as nutritionally deficient as it was) and second-hand clothes, and the luck not to have fallen prey to abuse, violence, and drugs.

I never expected much beyond struggle. This attitude made me strong. Later in life, when I had to deal with extreme difficulties, I was able to do so with equanimity and without letting the stress get to me.

When I encountered Friedrich Nietzsche’s 1888 saying that “what doesn't kill me makes me stronger,” it rang true.

In biology it has been shown to be absolutely true. There is even a name for it: Hormesis.

Hormesis is the stressing of an organism just enough to produce an adaptive response, but not so much that the stressor would kill the organism. The resulting adaptive response makes the organism stronger.

This mechanism applies to humans too. We can take advantage of it to extend our lives and make them healthier.

By stressing our cardiovascular system through aerobic exercise we can increase our levels of cardiorespiratory fitness and induce an adaptive response which improves our cardiovascular system (our blood flow, vessel smoothness, and more). Our ability to deal with possible cardiac events improves. Excessive training may lead to gastrointestinal issues and even to heart damage.

Stressing muscles through resistance training leads to hypertrophy (increased muscle size and strength). Lifting weights tears the muscle. With sufficient rest and nutrition, the torn muscle gets rebuilt bigger and stronger. Lifting too much, too hard, in a wrong form, or with insufficient rest, may result in serious, long-term injury.

Stressing our bodies through caloric restriction induces multiple adaptations, like autophagy and mitophagy—the internal “clean-up” of old and damaged cells and cell organelles. It has been shown to extend lives and inhibit age-related diseases in various animals. Important: To minimize deficiencies and harm, fasts and time-restricted diets should be accompanied by nutritionally-dense feedings.

The hormesis principle extends to other areas, most of which we should probably stay away from. For instance, restricting blood flow to the heart may make it stronger, and better able to deal with a heart attack. Exposure to low-dose radiation was found to be beneficial, again, because of the body’s hormetic response.

We can even avail ourselves of the stress responses of plants. This is called, Xenohormesis.

Isothiocyanates, like sulforaphane, are molecules that cruciferous plants produce in response to stress. Among other things, the plants hold two molecular packets separately: Glucoraphanin and the enzyme myrosinase. When the plant is attacked by, say, a herbivore bite or by microbes, the enzyme myrosinase comes into contact with the glucoraphanin and turns it into sulforaphane, which is toxic to insects and microorganisms. In humans, sulforaphane was found to exhibit anti-cancer, anti-inflammatory and anti-aging properties.

Similarly, plants produce flavonoids and stilbenes, like Resveratrol, in response to stress conditions. In humans, these compounds, too, were found to be anti-inflammatory and useful in treating or attenuating multiple conditions, including cancer, tissue injury, fatty liver, cerebral conditions like epilepsy, Alzheimer's Disease, Huntington's Disease, and Parkinson's Disease, and obesity-induced inflammation and insulin resistance.

To conclude, when properly harnessed, various types of stress can make us fitter, more resistant, healthier, and longer living. One big caveat: Never undertake any form of self-stressing without consulting your primary physician first. People have different conditions, different gene expressions, different genetic predispositions, and different tolerances, and those may pose risks, even at low levels of stress.